Air conditioning and other installations

ABSTRACT

The present invention relates to improvements in or relating to air conditioning and other installations, in particular to the removal of condensate and other liquids. We describe a method of preventing siphoning of a liquid through a pump having an inlet and an outlet, which outlet is coupled to a discharge line; the method comprising providing an air inlet valve in the discharge line. We also describe an air-inlet valve comprising a valve body having a liquid inlet and a liquid outlet and a through-bore therebetween further comprising an air-inlet in fluid communication with the through-bore. Preferably, the air-inlet comprises a non-return or one-way valve.

The present invention relates to improvements in or relating to airconditioning and other installations, in particular to the removal ofcondensate and other liquids.

In an air conditioning installation, a condenser is used to cool fluidwhich is used for space-cooling. The condenser produces condensate waterwhich must be removed. Typically, a positive displacement pump is usedas a condensate pump to remove condensate from a reservoir adjacent thecondenser to a drain via a small bore tube forming a discharge line. Afloat valve is used to sense when condensate needs evacuating from thereservoir and actuates the pump in response, switching off the pump whenall condensate has been removed. The condensate pump is a self-primingpump, but nevertheless, such pumps are typically very noisy when pickingup air as they start. Such pumps include a reciprocating metal piston ina cylindrical body and damage can be suffered when the pump runs with nowater in it.

Condensers are typically mounted at an elevated position with respect tothe drain. As such, once the pump has been switched off in response tothe float valve sensing no further condensate, condensate left upstreamof the condensate pump tends to siphon through the pump to the drainleaving the pump with no condensate in it and hence leading to increasednoise on the next start-up of the pump and increased wear on the pumpsurfaces and thus a decreased lifespan for the pump, often as little asa few months.

The present invention seeks to provide a solution to this problem.Accordingly, in its broadest sense, the present invention provides amethod of preventing siphoning of a liquid through a pump having aninlet and an outlet, which outlet is coupled to a discharge line; themethod comprising providing an air inlet valve in the discharge line.

Preferably, the air-inlet valve is positioned at a height not less thanslightly below the height of the outlet of the pump.

Accordingly, in a second aspect, the present invention provides anair-inlet valve. The air-inlet valve comprises a valve body having aliquid inlet and a liquid outlet and a through-bore therebetween furthercomprising an air-inlet in fluid communication with the through-bore.

Preferably, the air-inlet comprises a non-return or one-way valve. Morepreferably, the valve is a duck-bill valve.

The above and other aspects of the invention will now be described infurther detail with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of a first embodiment of an air-inlet valvein accordance with the present invention;

FIG. 2 is a schematic view of a portion of a typical air-conditioninginstallation incorporating the valve of FIG. 1;

FIG. 3 is an exploded view of the valve of FIG. 1;

FIG. 4 is a cross-sectional view of the valve of FIG. 1;

FIG. 5 is a cross-sectional view of a second embodiment of a valve inaccordance with the present invention; and

FIG. 6 is an exploded perspective view of the embodiment of FIG. 5.

The embodiment of the air-inlet valve in accordance with the presentinvention illustrated in the figures has a valve body 10, a liquid inlet11 and liquid outlet 12. Liquid inlet 11 is couplable to a source ofliquid, such as the outlet of a pump liquid outlet 12 is couplable to adrain, such as by means of a discharge line 24. The valve furthercomprises an air-inlet valve 13 within the valve body 10.

FIG. 2 shows the air-inlet valve in a typical air-conditioninginstallation in which a condenser 20 collects condensate water from theair-conditioning unit. This collects in a reservoir 21. A float valve 22senses when the water level in reservoir 21 reaches a predeterminedlevel and activates pump 23 in response thereto. Pump 23 removescondensate to drain through a discharge line 24. Air-inlet valve 10 isinterposed into discharge line 24 downstream of pump 23. Valve 10 can bepositioned slightly below pump 23 but is preferably positioned levelwith or above the height of pump 23.

The air-inlet valve is illustrated in further detail in FIGS. 3 and 4.Body 10 of the valve has a bore 30 communicating the inlet 11 and outlet12; and a cavity 31 in fluid communication with bore 30 by means of acommunicating line 32.

Cavity 31 is fitted with a uni-directional valve, as shown, in the formof a duck-billed elastomeric valve 33 held in position within cavity 31by means of a retaining cap 34.

As condensate flows through bore 30 as a consequence of the operation ofpump 23 air is caused to enter cavity 31 through valve 33 from theatmosphere.

As a consequence of the admission of air to the condensate flowingthrough the air-inlet valve, a body of water does not build updownstream of the valve. As a consequence, there is an inadequate weightof condensate liquid to cause condensate to siphon from that part of thedischarge line upstream of the pump (that is to say between float valve22 and pump 23). A full body of condensate is therefore maintained inpump 23 such that the pump noise and damage apparent with prior artarrangements is avoided.

An alternative construction is shown in FIGS. 5 and 6. In thisembodiment, valve body 40 consists of two couplable valve body halves41, 42. First valve body half 41 includes a liquid inlet 43 and anair-inlet 44. Second valve body half 42 includes a liquid outlet 45.

In the assembled air inlet valve, liquid inlet 43 and liquid outlet 45define a bore 50 through the valve.

Duck-billed elastomeric valve 33 is positioned between valve body halves41, 42 and held in place thereby, and is in communication with air inlet44 and a cavity 51 opening from bore 50. Second valve body half 42 alsoincludes internal ribs 52 to retain valve 33 in place and ensure thatthe valve is not compressed closed.

The operation of this embodiment is as per the first embodimentdescribed above. The two-part assembly simplifies moulding of thecomponents.

The present invention is of particular benefit for use with pistonpumps, for which this is a particular problem and so will find utilityalso in other uses, such as coffee machines. Such pumps typicallyinclude an internal valve, for example providing the self-primingfunction, typically providing a bias into a closed position against aspring force. The duck-billed valve 33, or other valve, will be selectedto be rated at less than the spring force of any internal pump valve toavoid siphoning.

1. A method of preventing siphoning of a liquid through a pump having aninlet and an outlet, which outlet is coupled to a discharge line; themethod comprising providing an air-inlet valve in the discharge line,the air-inlet valve arranged to admit air to the discharge line as theliquid flows through the discharge line.
 2. A method as claimed in claim1 wherein the air-inlet valve is positioned at about the height of, orabove the height of the outlet of the pump.
 3. A device for preventingsiphoning of a condensate liquid through a pump, wherein the devicecomprises a liquid inlet couplable to an outlet of the pump, and whereinthe device further comprises a liquid outlet forming a bore through thedevice with the liquid inlet, wherein the device further comprises anair-inlet in fluid communication with the bore and wherein the air-inletcomprises a uni-directional valve arranged to admit air into the devicein response to a flow of condensate liquid through the bore.
 4. A deviceas claimed in claim 3 wherein the valve is a duck-bill valve.
 5. Adevice as claimed in claim 4 wherein the valve is made of an elastomericmaterial.
 6. A device as claimed in claim 3 wherein the air-inletcomprises a cavity in fluid communication with the bore by means of acommunicating line.
 7. A device as claimed in claim 6 wherein the valveis a duck-bill valve and is held in position within the cavity by meansof a retaining cap.
 8. A device as claimed in claim 4 wherein theair-inlet comprises a cavity in fluid communication with the bore bymeans of a communicating line.
 9. A device as claimed in claim 8 whereinthe valve is held in position within the cavity by means of a retainingcap.
 10. A device as claimed in claim 5 wherein the air-inlet comprisesa cavity in fluid communication with the bore by means of acommunicating line.
 11. A device as claimed in claim 10 wherein thevalve is a duck-bill valve and is held in position within the cavity bymeans of a retaining cap.